Prepare the Cream Mixture:

1. Whip the Cream: In a large bowl, whip the heavy cream with an electric mixer on medium-high speed until soft peaks form.
2. Mix Mascarpone and Sugar: In a separate bowl, whisk together the mascarpone cheese, powdered sugar, and vanilla extract until smooth and creamy.
3. Fold in Whipped Cream: Gently fold the whipped cream into the mascarpone mixture until fully combined, creating a light and fluffy filling.

Prepare the Chocolate Layer:

4. Melt the Chocolate: In a heatproof bowl, melt the chocolate in the microwave or over a double boiler until smooth. Let it cool slightly before using.

Assemble the Lasagne:

5. Soak the Biscoff Cookies: Quickly dip each Biscoff cookie into coffee (optional) or milk to soften them slightly. Be careful not to soak them too long as they will become soggy.
6. First Layer of Cookies: Arrange a layer of soaked Biscoff cookies in the bottom of a 9×9-inch or similar-sized baking dish.
7. Add Cream Layer: Spread half of the cream mixture over the cookies, smoothing it into an even layer.
8. Add Chocolate Layer: Drizzle half of the melted chocolate over the cream layer.
9. Repeat Layers: Add another layer of soaked Biscoff cookies, followed by the remaining cream mixture and melted chocolate.
10. Top with Garnish: Finish by dusting the top with cocoa powder or crushed Biscoff cookies for a decorative and flavorful touch.

Chill and Serve:

11. Chill the Lasagne: Cover the dish with plastic wrap and refrigerate for at least 3.5 hours, or overnight, to allow the flavors to meld together.
12. Serve: Slice and serve chilled. This dessert is best enjoyed when the layers have fully set.